Verify empty observation direction property

pystac/extensions/sar.py

@@ -318,7 +318,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "SarExtension[T]":
             return cast(SarExtension[T], AssetSarExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"SAR extension does not apply to type {type(obj)}"
+                f"SAR extension does not apply to type '{type(obj).__name__}'"
             )
 
 

pystac/extensions/view.py

@@ -167,7 +167,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "ViewExtension[T]":
             return cast(ViewExtension[T], AssetViewExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"View extension does not apply to type {type(obj)}"
+                f"View extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod

tests/extensions/test_sar.py

@@ -1,10 +1,14 @@
 """Tests for pystac.extensions.sar."""
 
 import datetime
+from random import choice
 from typing import List
 import unittest
 
+from string import ascii_letters
+
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions import sar
 from pystac.extensions.sar import SarExtension
 from tests.utils import TestCases
@@ -180,6 +184,26 @@ def test_asset_ext_add_to(self) -> None:
 
         self.assertIn(SarExtension.get_schema_uri(), item.stac_extensions)
 
+    def test_should_return_none_when_observation_direction_is_not_set(self) -> None:
+        extension = SarExtension.ext(self.item)
+        extension.apply(
+            choice(ascii_letters),
+            choice(list(sar.FrequencyBand)),
+            [],
+            choice(ascii_letters),
+        )
+        self.assertIsNone(extension.observation_direction)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^SAR extension does not apply to type 'object'$",
+            SarExtension.ext,
+            object(),
+        )
+
 
 if __name__ == "__main__":
     unittest.main()

tests/extensions/test_view.py

@@ -1,4 +1,6 @@
 import json
+
+from pystac import ExtensionTypeError
 from pystac.collection import Collection
 import unittest
 
@@ -257,6 +259,16 @@ def test_asset_ext_add_to(self) -> None:
 
         self.assertIn(ViewExtension.get_schema_uri(), item.stac_extensions)
 
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^View extension does not apply to type 'object'$",
+            ViewExtension.ext,
+            object(),
+        )
+
 
 class ViewSummariestest(unittest.TestCase):
     def setUp(self) -> None: